Radiator fin-tube construction and method

ABSTRACT

A thin ribbon of core material passes through apparatus to form fin-tube radiator core material. A first pair of power-driven rolls forms &#39;&#39;&#39;&#39;louvers&#39;&#39;&#39;&#39; extending in a pattern transversely of the ribbon, with a gap between the louver patterns, and fine rectangular holes extending in a second pattern at the gap. The holes are formed by transverse alternately male and female combs inset in the first rolls. The holes rigidify the ribbon at the middle of the gap to resist tendency to fold or curve. The ribbon then passes through a pair of second rolls of star-shaped crosssection having slower peripheral speed than the first rolls. This arrangement causes the ribbon to fold at each gap with a flat center portion formed with the holes and bends to either side of the center portion. A third set of rolls beyond the second set has rubber-like rings which create an adjustable drag on the ribbon and complete formation of the folded ribbon with right angle bends at the folds. In the core, the flat center portions abut the radiator tubes and have a substantial area of heattransferance contact therewith. The solder on the tubes, when heated, flows by capillary action through the holes and when cooled forms heads which secure the fins in place.

Primary Examiner-Lowell A. Larson Attorney, Agent, or FirmJulian CaplanUnite States Patent 1 1 1111 3,850,018

Drosnin Nov. 26, 1974 RADIATOR FIN-TUBE CONSTRUCTION AND METHOD [57]ABSTRACT [76] Inventor: Sidney s. Drosnin, 2087 10th Ave., A thm rlbbonf re material passes through appara- San Francisco Calif, 941 16 tus toform fin-tube radiator core material. A first pair of power-driven rollsforms louvers" extending in a Fllfidi p 4 1973 pattern transversely ofthe ribbon,. with a gap between [21] APPL 399,683 the louver patterns,and fine rectangular holes extending in a second pattern at the gap. Theholes are formed by transverse alternately male and female U-s- Clombsinset in the first rolls The holes the rib- [5 n t bon at the of the gapto resist tendency to Fleld 0f Search o curve The ribbon then passesthrough a pair of ec- 113/113 ond rolls of star-shaped cross sectionhaving slower peripheral speed than the first rolls. This arrangement[56] References Cited causes the ribbon to fold at each gap with a flatcenter UNITED STATES PATENTS portion formed with the holes and bends toeither side- 544,1s0 8/1895 Lewis 72/186 of the Center P A third Set ofrolls beyond the 1 717,049 12 1902 stokes second set has rubber-likerings which create an ad- 1,546,195 7/1925 Briskin justable drag on theribbon and complete formation of 1,927,791 9/ a e the folded ribbon withright angle bends at the folds. 2,250,593 7/1941 M65961 In the core, theflat center portions abut the radiator 33671161 2/1968 Avaklanmtubes andhave a substantial area of heat-transferance 3:53; 72/187 contacttherewith. The solder on the tubes, when 3:766:873 10/1973 Narog"I:...........IIIQIIIII..- 72/186 heated flows by capnary actlo throughthe holes and when cooled forms heads which secure the fins in place.

, 6 Claims, 11 Drawing Figures RADIATOR FIN-TUBE CONSTRUCTION AND METHODThis application is an improvement on my US. Pat. No. 3,693,710.

This invention relates to a new and improved folded fin construction forradiators wherein a ribbon of thin sheet metal such as copper is formedin patterns of louvers with gaps between the louvers and with preferablyrectangular perforations in a second pattern centered in the gap betweenthe louvers, the ribbon being folded back and forth upon itself with thefold located to either side of the second pattern of holes so that thereis a relatively flat perforated surface between the folds which abutts aradiator tube. The flat surface provided greater heat conducting contactbetween the tin material and the tube. Further, solder on the outsidesurface of the tube, when suitably heated, flows by capillary actioninto the perforations and upon cooling forms heads similar to rivet headwhich produce a better bond between the fin and tube.

A feature of the invention is the forming of the socalled second patternof holes along the middle of the gap between the louvers on the ribbon.In addition to forming the perforations required for bonding, therectangular perforations provide rigidity so that when the ribbon isfolded there are substantially right angle bends on either side of thepattern of holes and the area where the holes occur is relatively flat,all for the purpose heretofore described.

Still another object of the invention is to provide a radiator corestructure consisting of tubes and fins with improved heat transferancefrom the tubes to the fins and a more secure bond between the fins andthe tubes, so that in the use of the radiator the bond will withstandrepeated and extreme pressure and temperature variatlons.

Another feature of the invention is the provision of apparatushereinafter described in detail for fabricating the fin stock rapidlyand efficiently without danger of the ribbon of stock being ruptured andwithout danger of the folds being improperly formed.

A still further object of the invention is to provide a method wherebythe louvers and holes are formed in the arrangement heretofore describedas the ribbon of metal is fed through first stand rollers and then toslow down the advance of the ribbons so that the folds form initially atthe flat portions of the ribbon, the degree of folding increasing untilthe flat surfaces are fabricated as has heretofore been described.

Other objects of the present invention will become apparent upon readingthe following specification and referring to the accompanying drawingsin which similar characters of reference represent corresponding partsin each of the several views.

In the drawings:

FIG. I is a top plan view of the apparatus of the present inventionbeing partially broken away to reveal parts of the machine below theupper level thereof.

FIG. 2 is a vertical sectional view taken substantially along the line2-2 of FIG. 1.

. FIG. 3 is an enlarged fragmentary sectional view through the firststand rollers. 1

FIG. 4 is a transverse sectional view through one of the rollers.

FIG. 5 is a view taken substantially along the line 5-5 of FIG. 3.

FIG. 6 is a view taken substantially along the line 6-6 of FIG. 5.

FIG. 7 is a side elevational view of a portion of the structure of FIG.2 in enlarged scale.

Fig. 8 is a side elevational view through an automobile radiator formedin accordance with the present invention.

FIG. 9 is a fragmentary sectional view taken substantially along theline 9-9 of FIG. 8.

FIG. 10 is a fragmentary sectional view taken substantially along theline 10-10 of FIG. 8.

FIG. 11 is a greatly enlarged sectional view of a portion of thestructure of FIG. 10 showing the contact between the fin structure and atube and the solder bond between the same.

Directing attention first to the apparatus best shown in FIGS. 1-7, abase plate 21 is provided extending substantially the entire length ofthe machine to which various vertical and horizontal members areattached by means of machine screws. Proceeding from top to bottom, asviewed in FIGS. 1 and 2, first roll stand 22 feeds the ribbon of sheetmetal from top to bottom and perforates the same. Said stand 22 ismounted on front and rear vertical guides 23 which are attached to baseplate 21 by any suitable means. Between the guides 23 is a bottom rest24 likewise fastened to plate 21 and extending vertically upwardly toabout the line of feed of the ribon 106. At the top, the guides 23 areinterconnected by longitudinal connectors 26.- Rotatably mounted instand 22 are top and bottom shafts 27, 28 each having at either end abushing 29. Bushings 29 are received in top and bottom bushing holders31 provided with inner and outer ears 32 so that the shafts 27, 28 arevertically movable in the gap between the guides 23 and a flat on thebottom of the lower holder 31 rests on the top of rest 24. Toaccommodate different thicknesses of sheet metal stock with which theapparatus is used, interchangeable spacers 36 are positioned between theholders 31 governing the distance between the shafts 27, 28.'To applythe requisite pressure to hold the shafts in position a hold-down orpressure screw 37 is theaded through connector 26 and has a spring 38bearing against the top of upper holder 31. Shafts 27, 28 rotatetogether and carry at their outer ends gears 33. A lateral extension ofupper shaft 27 comprises a drive shaft 34 which is driven by an electricmotor and gear reduction box (not shown). The same motor drives theentire apparatus.

Each shaft 27, 28 carries an end collar 39 immediately inward of bushing29 and between the end collars 39 are die collars 41, here shown asthree in number. Formed on the exterior of collars 41 are louver dies42' which cut and bend the sheet metal stock into the louvers in apattern. It will be understood that one of the louver dies is male and'one female and that these are staggered. Formed in collars 41 areradial slots 43. Fitting in slots 43 between the end collars 39 are malecombs 44 alternating with female combs 46. The combs 44, 46 are held inplace by retainer screws 47 which are threaded into one of the collars39 and have points bearing against the ends of the combs. The combs arethus locked in position. The male combs have male teeth 48 and thefemale combs female teeth 49, as best shown in FIGS. 4 and 6. Theseperforate the sheet metal stock in rectangular preforations which extendlengthwise of the direction of movement of the ribbon.

At the intake side of the first stand 22 (i.e., to the top as viewed inFIGS. 1 and 2) is a ribbon guide extension 51 on either side of themachine and fastened to the rearward guide 23. The extensions 51 areinterconnected by a cross rod 52 and carry ribbon side edge guides 53which are spaced apart along rod 52 the exact distance of the ribbonbeing fed and are so located that the ribbon is fed between theappropriate collars 41. It will be understood that ribbons of differentwidths are used depending upon the customers demand and thatby-and-large a single set of rollers at the first stand will accommodatea wide variety of different ribbon widths and patterns.

immediately to the left of first stand 22, as viewed in FIGS. 1 and 2,are top hold-down plate 56 having a forward edge 57 and a bottomhold-down plate 56a. The plates 56, 56a are horizontal and are spacedapart about the width of the material making up the ribbon after it hasbeen perforated. The forward edge 57 of top plate 56 is spacedrearwardly of second roll stand 61; and, as hereinafter explained, byreason of the gap between the edge 57 and the stand 61 the initial foldsin the ribbon stock occur in this gap.

Second roll stand 61 is formed with front and rear guides 62 on eitherside bolted to base plate 21 and is further provided with a bottom rest63 intermediate guides 62. At the top, longitudinal connector 64 boltedto the top of the guides 62 holds the parts in alignment. Stand 61 hasvertically aligned transverse top and bottom shafts 66, 67 each providedat each end with a bushing 68. Each bushing is received in a bushingholder 69 having projecting inner and outer/forward and rear ears 71which bridge the guides 62 so that the shafts 66, 67 may move verticallybetween guides 62 and the downward movement is limited by rest 63.Pressure adjustment screw 72 threaded through connector 74 engages theupper bushing holder 69 and determines the vertical position thereof.Shafts 66, 67 carry at at least one outer end gear 73 and one of thegears 73 is connected by means of idler gear 74 to one of the gears 33so that the shafts 27, 28 and 66, 67 turn synchronously. Each shaft 66,67 is formed with splines which provide top and bottom stars 76, 77 eachhaving a plurality of radial arms 78. The number of arms 78 is fewerthan the number of combs 44, 46 (i.e., vs 12) and the diameter of thestars is considerably less than that of the combs 44, 46. Hence theperipheral speed of the teeth on the combs 44, 46 is greater than theperipheral speed of the arms 78. As is best shown in FIG. 2, thecenterlines of stars 76, 77 are spaced apart so that there is nointermeshing similar to that of gears. The function of the arms 78 isprimarily to engage the ribbon of sheet metal as it enters the secondstand 61 and retard its movement relative to the movement imparted bythe first stand. Since there is a gap forwardly of edge 57, the resultis that the ribbon of material folds, forming initial folds 111 whichare less than right angle and later forming right angle folds. Thesecond function of stars 76, 77 is to insure that the material is fedproperly beyond the second stand.

Third roll stand 81 has top and bottom side plates 82, 82a-on eitherside of the machine which support opposite ends of transverse horizontalveritcally aligned top and bottom shafts 84, 83. Each bottom side plate82a is bolted to forward guide 62 of the second stand. On either side isa horizontal extension 98 bolted to forward guide 62 and which carriesthe top slide plate 82. v

There is a vertical slot (not shown) in the side guide 62 whereextension 98 is attached to provide for vertical adjustment. Bottomshaft 83 at either end is journaled in side plate 82a. Top shaft 83 ateither end carries an eccentric bushing 86 which is rotatably journaledin side plate 82. Adjustment screw 87 threaded into side plate 82 bearsagainst bushing 86, and by turning screw 87 the vertical position ofshaft 84 may be adjusted. Horizontal bottom plate 88 formed withopenings 89 underlies shaft 83 and is secured to base plate 21.Horizontal top plate 91 is bolted to plates 82 and is disposed belowshaft 84 and is spaced above plate 88 a variable distance depending uponthe material being formed. Top plate 91 has rearward extending combs 92which are interposed between shafts 83, 84 and prevent the materialbeing handled from wrapping around the shafts.

Side edge guides 93 are adjustably positioned on rod 95 supported byextensions 98. Guides 93 hold the material aligned. Also supported onextensions 98 is cross tie 96 from which top hold-down plate 94 extendsforwardly to adjacent shafts 83, 84.

The periphery of each shaft 83, 84 carries a plurality of rubber orrubber-like rings 97 which are fixed in such manner as to fit in thespaces where there are no perforations 108 or louvers 107 formed on theribbon 106 being handled. The shafts 83, 84 are not power driven. Therubber rings 97 create a frictional resistance to movement of the stockthrough the machine and insure that the stock is folded in a mannerhereinafter described.

Forward of third stand 81 is a cut-off stand 101 which contains a bladeactuated by cylinder 102 to cut the stock into required length. Thedetails of cut-off stand 101 are conventional and are not hereindescribed in detail.

As is explained in my US. Pat. No. 3,693,7l0, and particularly referringto FIG. 8 of the drawings of said patent, an alternative form ofapparatus, which is standard in radiator fin rolling equipment, employsmodifled star wheels 42, 43 in which the means for forming perforationsare installed. As will be readily understood by one skilled in the art,the pins 47 of said prior patent may be replaced with male combs 44 ofthe present invention and the recesses 48 of said prior patent may bereplaced with the female combs 46 of the present invention. Thelouver-forming dies 42 of the present invention may be installed on theflanks of the stars of said prior patent star wheels. Such alternatestar wheels may be incorporated in the present invention in the firststand of the apparatus, replacing the rollers replacing the dies 42 andcombs 44 and 46 and the collars 41. The ribbon stock 106 is fed fromsuch first stand between the plates 56, 56a and into the second stand.The principle of operation of the modified apparatus is essentially thesame as has been described with reference to FIGS. 1-7 of theaccompanying drawings.

Directing attention now to the method of the present invention, a thinribbon 106 is provided, the width of the ribbon and its thicknessdepending upon the specifications of the radiator to be formed. Apreferred material of construction of ribbon 106 is copper, since it isheat conductive and easily worked and also has an affinity for solder.The ribbon 106 is fed from top to bottom as viewed in FIGS. 1 and 2, andthe speed is controlled by the speed of rotation of shafts 27, 28. Asthe ribbon 106 is fed through the first stand, two operations areperformed thereon. Louvers 107 are cut and outwardly bent by the louverdies 42 which are formed on the periphery of the diecollars 41. The diecollars 42 are formed with gaps there-between, and in the center of eachgap are combs 44, 46 which cooperate to form in the ribbon 106 holes 108which are rectangular, having their longer dimension in the direction offeed of the ribbon 106. The cutting of the holes 108, as best shown inFIGS. 3, 5 and 6, forms cusps 109 which rigidify the material around theholes 108, thereby providing resistance to bending. As the ribbonapproaches the second stand, because the second stand has a lowerperipheral speed than the first stand, incipient folds 111 of less than90 are formed in the ribbon. After passing through the second stand, theribbon is further retarded by the third stand and this causes the ribbonto assume a shape, as best shown in FIG. 11, wherein the area betweenthe louvers 107 is formed with right angle folds 112 and flats 113between the right angle folds which are at right angles to the portionof the ribbon carrying the louvers 107. An important difference betweenthe ribbon of the present invention and that of the prior US. Pat. No.3,693,710 is that instead of being rounded, the areas 113 between thelouvered portions are flat and at right angles.

A conventional radiator core is shown in FIG. 8 having pluralities oftubes 116 preferably of oblong shape with rounded corners between whichthe fins are interposed. Directing attention again to FIG. 11, the flatportion 113 is flat against the side of tube 116 so that heattransferance is at a maximum. Ordinarily, the tubes 116 are coated withsolder and after the fins are in place against the tubes 116, theassembly is heated in a furnace so that the solder melts. The cusps 109surrounding the holes 118 assist the capillary action, drawing a portionof the solder 117 from the side of the tube 116 through the hole 108 andbeyond. When the assembly is cooled by removal from the furnace, heads118 of solder formaround the cusps 109 and securely lock the finsrelative to the tubes 116. Severe heat and pressure conditions exist inmodern radiators and the formation of the heads 118 resist breakagewhich might otherwise occur under the stress conditions.

What is claimed is:

1. Apparatus for forming radiator fin stock from a thin ribbon of sheetmetal comprising a frame, a first stand having an upper rotary memberand a lower rotary member rotatably mounted in said frame in verticalalignment, means for rotating said rotary members together, said rotarymembers having mating louver forming dies and transverse mating combs,alternate combs formed with pluralities of male and female teeth, saidteeth shaped to form rectangular holes in said ribbon as it is advancedby said rotary members said dies and combs positioned in said rotarymembers to form on said ribbon longitudinally elongated louversseparated by short gaps and rectangular holes in said gaps, there beingnarrow areas at said gaps between said holes and said louvers, a secondstand comprising at least one star-shaped roll rotating synchronouslywith said rotary members and hold down plates between said stands, onesaid plate terminating spaced from said second stand, said star-shapedroll positioned to be engaged by said ribbon and having a peripheralspeed less than that of said rotary members to reduce the linear speedof said ribbon and cause the ribbon to form incipient folds at saidnarrow areas as said ribbon travels from said rotary members to saidstar-shaped roll; and a third stand having means to form said ribboninto a shape with parallel first panels each formed with louvers andflat short second panels containing said holes, said flat panelsperpendicular to said first panels.

2. Apparatus according to claim 1 in which each said rotary member is aroller, said dies formed on said rol ler and said dies separated byperipheral transverse arcuate spaces between adjacent dies, said combsrecessed into said spaces and occupying most of said spaces with narrowareas to either side of said combs where said ribbon is formedimperforate.

3. Apparatus according to claim 2 in which each said roller comprises ashaft, a plurality of die collars on said shaft, a pair of end collarson said shaft on the outsides of said die collars, means to cause all ofsaid collars to rotate with said shaft, said die collars formed withaligned radial slots to receive said combs, said die collars formed withalternating male: and female louver dies.

4. Apparatus according to claim 3 in which one of said collars is formedwith tapped holes to receive set screws bearing against said combs tolock said combs in place in said rollers.

5. Apparatus according to claim 3 in which said frame is formed with avertical slot and which further comprises a bushing around each saidshaft, 21 bushing holder receiving each said bushing, cooperating meanson each said holder and the margin of said frame on either side of saidslot guiding said rotary member for movement toward and away from theopposite rotary member, and adjustable means for applying pressure tomove the axes of rotation of said rotary members toward and away fromeach other.

6. Apparatus according to claim 5 which further comprises replaceablespacers interposed between bushing holders to limit the minimum distancebetween said rotary members, said spacers being of differentthicknesses.

1. Apparatus for forming radiator fin stock from a thin ribbon of sheetmetal comprising a frame, a first stand having an upper rotary memberand a lower rotary member rotatably mounted in said frame in verticalalignment, means for rotating said rotary members together, said rotarymembers having mating louver forming dies and transverse mating combs,alternate combs formed with pluralities of male and female teeth, saidteeth shaped to form rectangular holes in said ribbon as it is advancedby said rotary members said dies and combs positioned in said rotarymembers to form on said ribbon longitudinally elongated louversseparated by short gaps and rectangular holes in said gaps, there beingnarrow areas at said gaps between said holes and said louvers, a secondstand comprising at least one star-shaped roll rotating synchronouslywith said rotary members and hold down plates between said stands, onesaid plate terminating spaced from said second stand, said star-shapedroll positioned to be engaged by said ribbon and having a peripheralspeed less than that of said rotary members to reduce the linear speedof said ribbon and cause the ribbon to form incipient folds at saidnarrow areas as said ribbon travels from said rotary members to saidstar-shaped roll; and a third stand having means to form said ribboninto a shape with parallel first panels each formed with louvers andflat short second panels containing said holes, said flat panelsperpendicular to said first panels.
 2. Apparatus according to claim 1 inwhich each said rotary member is a roller, said dies formed on saidroller and said dies separated by peripheral transverse arcuate spacesbetween adjacent dies, said combs recessed into said spaces andoccupying most of said spaces with narrow areas to either side of saidcombs where said ribbon is formed imperforate.
 3. Apparatus according toclaim 2 in which each said roller comprises a shaft, a plurality of diecollars on said shaft, a pair of end collars on said shaft on theoutsides of said die collars, means to cause all of said collars torotate with said shaft, said die collars formed with aligned radialslots to receive said combs, said die collars formed with alternatingmale and female louver dies.
 4. Apparatus according to claim 3 in whichone of said collars is formed with tapped holes to receive set screwsbearing against said combs to lock said combs in place in said rollers.5. Apparatus according to claim 3 in which said frame is formed with avertical slot and which further comprises a bushing around each saidshaft, a bushing holder receiving each said bushing, cooperating meanson each said holder and the margin of said frame on either side of saidslot guiding said rotary member for movement toward and away from theopposite rotary member, and adjustable means for applying pressure tomove the axes of rotation of said rotary members toward and away fromeach other.
 6. Apparatus according to claim 5 which further comprisesreplaceable spacers interposed between bushing holders to limit theminimum distance between said rotary members, said spacers being ofdifferent thicknesses.